Human immunodeficiency virus (HIV) infection and related diseases are a major public health problem worldwide. A virally encoded integrase protein mediates specific incorporation and integration of viral DNA into the host genome. Integration is necessary for viral replication. Accordingly, inhibition of HIV integrase is an important therapeutic pursuit for treatment of HIV infection of the related diseases.
Human immunodeficiency virus type 1 (HIV-1) encodes three enzymes which are required for viral replication: reverse transcriptase, protease, and integrase. Although drugs targeting reverse transcriptase and protease are in wide use and have shown effectiveness, particularly when employed in combination, toxicity and development of resistant strains have limited their usefulness (Palella, et al N. Engl. J. Med. (1998) 338:853-860; Richman, D. D. Nature (2001) 410:995-1001). There is a need for new agents directed against alternate sites in the viral life cycle. Integrase has emerged as an attractive target, because it is necessary for stable infection and homologous enzymes are lacking in the human host (LaFemina, et al J. Virol. (1992) 66:7414-7419). The function of integrase is to catalyze integration of proviral DNA, resulting from the reverse transcription of viral RNA, into the host genome, by a stepwise fashion of endonucleolytic processing of proviral DNA within a cytoplasmic preintegration complex (termed 3′-processing or “3′-P”) with specific DNA sequences at the end of the HIV-1 long terminal repeat (LTR) regions, followed by translocation of the complex into the nuclear compartment where integration of 3′-processed proviral DNA into host DNA occurs in a “strand transfer” (ST) reaction (Hazuda, et al Science (2000) 287:646-650; Katzman, et al Adv. Virus Res. (1999) 52:371-395; Asante-Applah, et al Adv. Virus Res. (1999) 52:351-369). Although numerous agents potently inhibit 3′-P and ST in extracellular assays that employ recombinant integrase and viral long-terminal-repeat oligonucleotide sequences, often such inhibitors lack inhibitory potency when assayed using fully assembled preintegration complexes or fail to show antiviral effects against HIV-infected cells (Pommier, et al Adv. Virus Res. (1999) 52:427-458; Farnet, et al Proc. Natl. Acad. Sci. U.S.A. (1996) 93:9742-9747; Pommier, et al Antiviral Res. (2000) 47:139-148.
HIV integrase inhibitory compounds with improved antiviral and pharmacokinetic properties are desirable, including enhanced activity against development of HIV resistance, improved oral bioavailability, greater potency and extended effective half-life in vivo (Nair, V. “HIV integrase as a target for antiviral chemotherapy” Reviews in Medical Virology (2002) 12(3):179-193). Three-dimensional quantitative structure-activity relationship studies and docking simulations (Buolamwini, et al Jour. Med. Chem. (2002) 45:841-852) of conformationally-restrained cinnamoyl-type integrase inhibitors (Artico, et al Jour. Med. Chem. (1998) 41:3948-3960) have correlated hydrogen-bonding interactions to the inhibitory activity differences among the compounds.
Certain HIV integrase inhibitors have been disclosed which seek to block integration in extracellular assays and exhibit antiviral effects against HIV-infected cells (Anthony, et al WO 02/30426; Anthony, et al WO 02/30930; Anthony, et al WO 02/30931; WO 02/055079; Zhuang, et al WO 02/36734; U.S. Pat. No. 6,395,743; U.S. Pat. No. 6,245,806; U.S. Pat. No. 6,271,402; Fujishita, et al WO 00/039086; Uenaka et al WO 00/075122; Selnick, et al WO 99/62513; Young, et al WO 99/62520; Payne, et al WO 01/00578; Jing, et al Biochemistry (2002) 41:5397-5403; Pais, et al J. Med. Chem. (2002) 45:3184-94; Goldgur, et al Proc. Natl. Acad. Sci. U.S.A. (1999) 96:13040-13043; Espeseth, et al Proc. Natl. Acad. Sci. U.S.A. (2000) 97:11244-11249). Recent HIV integrase inhibitors are shown in WO 2005/016927, WO 2004/096807, WO 2004/035577, WO 2004/035576 and US 2003/0055071.
There exists a need to find additional compounds for the treatment of HIV, particularly, improved integrase inhibitors having beneficial properties and good efficacy.